Undercutting-knife



2 Sheets-Sheet 2.

(No Model.)

W. M. DWIGHT.

UNDBRGUTTI'NG KNIFE. No. 354,974. Patented-Dec. 28; 1 886.

- NITED STATES PATENT Grace.

XVILLIAM M. DIVIGHT, OF DETROIT, MICHIGAN. v

UNDERCUTTING-KNIFE.

SPECIFICATION forming pan: of Letters Patent No. 354,974, dated December 28, 1886.

Application filed March 4, 1886. Serial No. 194,028. (No model.)

To all whom it may concern: Beit known that I, WILLIAM M. DWIGHT,

.of Detroit, in the county of Wayne and State of Michigan, have invented a new and useful Improvement in Undercutt-ing Knives, of which the following is a specification.

My invention relates to an improved knife for undercutting straight-sided grooves for use in the invention shown in my Patent No. 329, 824. v

Figure 1 is a side elevation of part of a planing-machine; Figs. 2 and 3, end elevations of a board, showing the sti'aight sided and undercut grooves. Fig. 4 is a front elevation of my improved knife and its support. Fig. 6 is a side elevation of the same, and Fig. 5 is a bottom plan view of that part of the knife at the right of line a: 00, Fig. 6.

1 represents part of a planing-machine, the under-surfacing cylinder of which is represented by 2 and carries two knives, 3, thereon adapted to cut straight-sided grooves in the under surface of a board passing through the machine, as shown in Fig. 2.

' 10 represents a post to carry my improved knife, and is to be secured to thebed of the planing-machine, or a suitable support,5,

thereon, either by being made on a shoe, 11,

- to be secured to the machine by a bolt, 4, or

in any other suitable manner. 4

My improved knife consists of a shank, 8, adapted to be bolted to post 10, and of such width that it will enter the groove made by knives 3, and an enlarged head, A, on the end of the shank, too wide to enter said groove,

and having cutting-edges7 formed on one end the cutting edges 7 on that end of the head A which is nearest the shank 8, so that the knife will be drawn through the groove, in stead of being pushed, as this causes the shavings to pass away from the post 10, instead of toward said post, as would be the case if the knife were pushed through the groove, and

thus obviates clogging, and also enables me to make the shank 8 shorter, and causes the knife to run steadier; but the cuttingedges 7 may be formed on the other end of head A and the knife pushed through the groove without departing from my invention. 9 9 represent two bolts,which hold shank 8 to post 10, and I usually make shank 8 bent and secure it to the post, as shown; but this is a mere matter of mechanical cohvenience.

In using my invention, the shank 8 enters the groove made by knives 3 as the board is fed throughthe machine; but the head A is too wide to enter said groove, and its cuttingedges out out two shavings of the shape shown in dotted lines in Fig. 2, and the chamfers 12 force these shavings inward and downward, so that they drop clear of the knife. The

wings 6 prevent splitting of the board in ad vance of the knife, and also insure complete separation of the shavings, which otherwise would sometimes stick to the edges of the the cutting-edges through the groove to force the shavings downward in advance of thehead, substantially as described.

2. A knife for undercutting a groove, consisting of a shank adapted to enter the groove,

' and having an enlarged head provided with cutting-edges at one end and chamfered toward the center of the knife for throwing the shavings toward the center thereof and downward, substantially as described.

'WILLIAM M. DWIGHT.

Witnesses:

SUMNER CoLLINs, GEo. H. LOTHROP. 

